Cut out the Preamp and go Direct?

Hello to AS


With no plans for phono, or other analog sources I am trying to figure out if directly connecting a PS Audio Direct Stream DAC to an amp and bypassing the preamp will yield the same or possibly better sound?


What are the gains and what are losses?

I have a similar setup with an NAD M51.

If the digital volume control is sufficiently "deep" you won't lose resolution if it controls gain.

I've had multiple Preamps (none so fine as mentioned here) and they all mask some data.

I vote for fewer buttons, knobs and parts.
 
Now in my 60's, I am a firm disciple of the digital camp, preferring to spin silver discs than vinyl albums for much of the time.

Because I have a large record collection and many LP's collected since the 70's, that I have never duplicated on CD, a good preamp is a must for me.

I consider myself very fortunate to own not only one of the generally considered 'best' preamps in the Conrad Johnson GAT Series 2, but also a top-tier digital front end in the dCS Vivaldi 2.0 "full stack."

The digital volume control of the Vivaldi DAC is recognised as being particularly good and I have, indeed, spent many hours listening to my system playing 'direct' from the DAC into my Conrad Johnson Premier 350SA power amp and with the GAT 2 in circuit.

On first listening to the Vivaldi DAC driving the power amp direct, the sound is impressive, with plenty of detail and a palpable quality to the music. I have the ability, via the Vivaldi DAC to vary the output from 0.2 volt through to 6 volts in four increments and have experimented at the lower end of the scale in an effort to raise the DAC volume control and therefore the bit resolution as much as possible while keeping within a reasonable listening volume for my room.

Initially very impressive, I found my attention starting to wander after a time, but this was never the case when the GAT 2 preamp was in circuit, with the Vivaldi DAC at maximum 0.0db volume.

The insertion of a quality preamp, for me, in my system, is preferred and leads to many hours of fatigue-free listening pleasure, drawing me into the music more.

I hope I have been able to convey my preference for a preamp in the context of my system.

Other listeners may, indeed prefer the directly-driven approach. It's certainly not "night and day" and for me, proves that the dCS Vivaldi 2.0 DAC has an excellent quality digital volume control.

fullsizeoutput_8fd by Steve Coward, on Flickr
 
I prefer my Music First TVC to several active preamps I've tried. I also compared it with MSB direct to my amp and preferred the system with the MF inserted.
 
Thanks all!

Tough one as on paper direct path makes the most sense, however, listening revealed using the pre-amp for all the reasons stated. It’s in, staying put and I’m happy!
 
I also subscribe to the preamp camp, but I think that the manufacturers should get more with the groing trend and come up with a 'minimalist' line that would provide the same sound quality as their best, but limit the inputs/outputs, as enough of us it seems have abandoned all but our digital related single input.
 
I am also using MFA TVC and MSB. I also prefer MFA between MSB and amp.
 
I also subscribe to the preamp camp, but I think that the manufacturers should get more with the groing trend and come up with a 'minimalist' line that would provide the same sound quality as their best, but limit the inputs/outputs, as enough of us it seems have abandoned all but our digital related single input.

I agree with this, and this is actually what I wanted from my preamp as well, no input selection, only volume control. The MFA Baby Classic actually is like this, but when I upgraded to the Baby Reference top model I was talked into keeping the original inputs and I don't regret it, even if I'm never going to use them it's nice to be able to flip to another input sometimes, and it's not really the input connections that costs money in the unit. But, someone actually got this built... as some manufactures can do whatever you want... :)

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I can understand that there is no need for a pre-amp if you are streaming only. This is audio 2.0. With new speaker generations to come like the KEF LS-50 wireless where the Roon endpoint sits in the speaker I can imagine that in the near future most audio set-ups will exist of an iPad and a set of fully integrated speakers.

Having said that I do own a PS Audio DS Junior. And I am extremely happy with the sound quality and all the options. When I selected the DSJ a few criteria were very important: Roon endpoint, the development of MQA compatibility and very importantly that there is a real volume control. This allows a real high-end volume control with the iPad. Therefore the basis for direct connection to power amps or active speakers is there.

However there is one point that is not perfect with the DSJ that is not perfect in my opinion. When switching off (and also when switching songs in different formats) there is a soft plopping noise.
I don't know how strong this is with direct connections but when this is solved the direct connection should work perfect. I do know in the 6 Months I have my PS Audio that they are very active in continuous software improvements.
 
The preamp's function is 4-fold:

1) add any needed gain
2) control the volume
3) select inputs
4) control the interconnect cable

Of these four, the last is the least understood. Passive controls have no control of the interconnect at all, so a successful system that uses a passive will have had a lot of cable audition and likely has really short interconnects to boot.

Put another way, if the line section is really doing its job right, the interconnect cable will not be that important. Preamps often have better volume controls than digital systems too, so the way to take advantage of the preamp's abilities is to run the digital volume all the way up and then use the preamp's control.
 
Going direct does not mean you are operating without a preamplifier in the signal path. It means you are using the preamplifier built into the DAC, DAC/Player, or Music Server/DAC. These preamplifiers are rarely in the same league as separate high-end preamplifiers, being pared down to what is necessary to output the analog signal and nothing more. I am not saying all variable output stages in DAC's and other digital components are afterthoughts, but they certainly are not given the same level of attention as stand alone preamplifiers. Certainly some variable output stages on digital components are quite good, unfortunately they usually don't measure up under close comparison and scrutiny. I prefer the fixed line level outputs going direct to my preamplifier and then to my amplifiers. Don't be fooled into thinking you have bypassed a preamplifier by going direct.
 
Although going direct may work well in certain systems, I believe that in the majority of cases, having a pre-amp is better. The technical reasons are:

1. Impedance mismatch - this is also one of the causes of using the same brand and product line of pre-amp and power amp combo is often better than mixed brands, if the impedance is not matched.

2. Volume - most digital sources have digital volume only. A high quality analog volume is generally superior for the simple reasons that the noise floor from the source is lowered, and digital bits are not thrown away. (However, there are arguments that 32-bit digital volume is good enough.)

3. How the source is designed - this is a little known aspect in this type of discussions. A certain kind of design decision is going to impact whether a direct connection is good or not. However, this cannot be found from specification sheet, and I believe most sources do not choose this design for other good technical reasons as they are not designed to drive power amps.

That being said, if all of the above are taken care of, in a system with enough gain but not too much, then a direct connection can work well and be very neutral.
 
There could be another element at play. I also tried going directly from my digital front end (an Oppo BDP-105 at the time) directly into my amplifier and found that the top end was fairly rolled off versus using a pre-amp in the loop. After doing a little digging, I discovered that the output impedance of the player wasn't a great match for the input impedance of the amplifier. I suppose it's like all the other "hacks" we do in audio: try it and see.
 
Sold my Nagra jazz and use my Nagra hd-dac directly into my Nagra amps. The hd-dac uses the same volume control as the jazz and the sound is totally spot on.
i use a ADC from my phono stage into the dac...
 
Now in my 60's, I am a firm disciple of the digital camp, preferring to spin silver discs than vinyl albums for much of the time.

Because I have a large record collection and many LP's collected since the 70's, that I have never duplicated on CD, a good preamp is a must for me.

I consider myself very fortunate to own not only one of the generally considered 'best' preamps in the Conrad Johnson GAT Series 2, but also a top-tier digital front end in the dCS Vivaldi 2.0 "full stack."

The digital volume control of the Vivaldi DAC is recognised as being particularly good and I have, indeed, spent many hours listening to my system playing 'direct' from the DAC into my Conrad Johnson Premier 350SA power amp and with the GAT 2 in circuit.

On first listening to the Vivaldi DAC driving the power amp direct, the sound is impressive, with plenty of detail and a palpable quality to the music. I have the ability, via the Vivaldi DAC to vary the output from 0.2 volt through to 6 volts in four increments and have experimented at the lower end of the scale in an effort to raise the DAC volume control and therefore the bit resolution as much as possible while keeping within a reasonable listening volume for my room.

Initially very impressive, I found my attention starting to wander after a time, but this was never the case when the GAT 2 preamp was in circuit, with the Vivaldi DAC at maximum 0.0db volume.

The insertion of a quality preamp, for me, in my system, is preferred and leads to many hours of fatigue-free listening pleasure, drawing me into the music more.

I hope I have been able to convey my preference for a preamp in the context of my system.

Other listeners may, indeed prefer the directly-driven approach. It's certainly not "night and day" and for me, proves that the dCS Vivaldi 2.0 DAC has an excellent quality digital volume control.

fullsizeoutput_8fd by Steve Coward, on Flickr

In my main system I use a GAT1. The Dac is the McIntosh MDA1000 with variable outputs too. As you and many other friends here stated, I never preferred the MDA direct into the amps compared to using a separate preamp. And this was the case not only with the GAT but with about 10 different preamps I used in 5 years.
The MDA direct sounds thinner and fatigue appears quickly.
A great preamp is a must for me in high end hifi. In the couple preamp-power amp, its influence is much higher than the one of the power amp imho. It gives the texture, the grain, the frequency bandwidth, the transparency and details.
Seems not very difficult to build great sounding power amps for most brands. Building a great sounding preamp is an other challenge.
 
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